I've tried 5 different 4X media types on my Cendyne/Pioneer DVR-105 burner. I've had the best luck with the Ritek 4X for quality (no coasters) and compatibility (plays on all my DVD players). I'm working on my second Ritek 100 pack. I've had the worst luck with Princo (1 out of 10 are coasters) and less compatibility (probably due to the quality). Although, I might give BeALL a try since it's getting good ratings at DVDRHELP.COM.
